Attributed to John Fitzgibbon, Earl of Clare (cf. NUC pre-1956). He used the name Mr. Paddy Whack for a work published in 1799 (cf. DNB).
Answers: A letter from Mr. John Bull, of London, to Mr. Paddy Whack, of Dublin (1792)
John Bull and Paddy Whack are nicknames for an Englishman and an Irishman respectively.
Letter from the Society of United Irishmen: 7 p. at end.
Microfilm. New Haven, CT : Yale University Library, 2002. 1 microfilm reel ; 35 mm. Copy filmed: BEIN NZ 792ck. The circular letter from the United Irishmen is wanting.